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//===- LexicalScopes.cpp - Collecting lexical scope info ------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements LexicalScopes analysis.
//
// This pass collects lexical scope information and maps machine instructions
// to respective lexical scopes.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "lexicalscopes"
#include "llvm/CodeGen/LexicalScopes.h"
#include "llvm/Function.h"
#include "llvm/Analysis/DebugInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/FormattedStream.h"
using namespace llvm;
LexicalScopes::~LexicalScopes() {
releaseMemory();
}
/// releaseMemory - release memory.
void LexicalScopes::releaseMemory() {
MF = NULL;
CurrentFnLexicalScope = NULL;
DeleteContainerSeconds(LexicalScopeMap);
DeleteContainerSeconds(AbstractScopeMap);
InlinedLexicalScopeMap.clear();
AbstractScopesList.clear();
}
/// initialize - Scan machine function and constuct lexical scope nest.
void LexicalScopes::initialize(const MachineFunction &Fn) {
releaseMemory();
MF = &Fn;
SmallVector<InsnRange, 4> MIRanges;
DenseMap<const MachineInstr *, LexicalScope *> MI2ScopeMap;
extractLexicalScopes(MIRanges, MI2ScopeMap);
if (CurrentFnLexicalScope) {
constructScopeNest(CurrentFnLexicalScope);
assignInstructionRanges(MIRanges, MI2ScopeMap);
}
}
/// extractLexicalScopes - Extract instruction ranges for each lexical scopes
/// for the given machine function.
void LexicalScopes::
extractLexicalScopes(SmallVectorImpl<InsnRange> &MIRanges,
DenseMap<const MachineInstr *, LexicalScope *> &MI2ScopeMap) {
// Scan each instruction and create scopes. First build working set of scopes.
for (MachineFunction::const_iterator I = MF->begin(), E = MF->end();
I != E; ++I) {
const MachineInstr *RangeBeginMI = NULL;
const MachineInstr *PrevMI = NULL;
DebugLoc PrevDL;
for (MachineBasicBlock::const_iterator II = I->begin(), IE = I->end();
II != IE; ++II) {
const MachineInstr *MInsn = II;
// Check if instruction has valid location information.
const DebugLoc MIDL = MInsn->getDebugLoc();
if (MIDL.isUnknown()) {
PrevMI = MInsn;
continue;
}
// If scope has not changed then skip this instruction.
if (MIDL == PrevDL) {
PrevMI = MInsn;
continue;
}
// Ignore DBG_VALUE. It does not contribute to any instruction in output.
if (MInsn->isDebugValue())
continue;
if (RangeBeginMI) {
// If we have already seen a beginning of an instruction range and
// current instruction scope does not match scope of first instruction
// in this range then create a new instruction range.
InsnRange R(RangeBeginMI, PrevMI);
MI2ScopeMap[RangeBeginMI] = getOrCreateLexicalScope(PrevDL);
MIRanges.push_back(R);
}
// This is a beginning of a new instruction range.
RangeBeginMI = MInsn;
// Reset previous markers.
PrevMI = MInsn;
PrevDL = MIDL;
}
// Create last instruction range.
if (RangeBeginMI && PrevMI && !PrevDL.isUnknown()) {
InsnRange R(RangeBeginMI, PrevMI);
MIRanges.push_back(R);
MI2ScopeMap[RangeBeginMI] = getOrCreateLexicalScope(PrevDL);
}
}
}
/// findLexicalScope - Find lexical scope, either regular or inlined, for the
/// given DebugLoc. Return NULL if not found.
LexicalScope *LexicalScopes::findLexicalScope(DebugLoc DL) {
MDNode *Scope = NULL;
MDNode *IA = NULL;
DL.getScopeAndInlinedAt(Scope, IA, MF->getFunction()->getContext());
if (!Scope) return NULL;
if (IA)
return InlinedLexicalScopeMap.lookup(DebugLoc::getFromDILocation(IA));
return LexicalScopeMap.lookup(DL.getScope(Scope->getContext()));
}
/// getOrCreateLexicalScope - Find lexical scope for the given DebugLoc. If
/// not available then create new lexical scope.
LexicalScope *LexicalScopes::getOrCreateLexicalScope(DebugLoc DL) {
MDNode *Scope = NULL;
MDNode *InlinedAt = NULL;
DL.getScopeAndInlinedAt(Scope, InlinedAt, MF->getFunction()->getContext());
if (InlinedAt) {
// Create an abstract scope for inlined function.
getOrCreateAbstractScope(Scope);
// Create an inlined scope for inlined function.
return getOrCreateInlinedScope(Scope, InlinedAt);
}
return getOrCreateRegularScope(Scope);
}
/// getOrCreateRegularScope - Find or create a regular lexical scope.
LexicalScope *LexicalScopes::getOrCreateRegularScope(MDNode *Scope) {
LexicalScope *WScope = LexicalScopeMap.lookup(Scope);
if (WScope)
return WScope;
LexicalScope *Parent = NULL;
if (DIDescriptor(Scope).isLexicalBlock())
Parent = getOrCreateLexicalScope(DebugLoc::getFromDILexicalBlock(Scope));
WScope = new LexicalScope(Parent, DIDescriptor(Scope), NULL, false);
LexicalScopeMap.insert(std::make_pair(Scope, WScope));
if (!Parent && DIDescriptor(Scope).isSubprogram()
&& DISubprogram(Scope).describes(MF->getFunction()))
CurrentFnLexicalScope = WScope;
return WScope;
}
/// getOrCreateInlinedScope - Find or create an inlined lexical scope.
LexicalScope *LexicalScopes::getOrCreateInlinedScope(MDNode *Scope,
MDNode *InlinedAt) {
LexicalScope *InlinedScope = LexicalScopeMap.lookup(InlinedAt);
if (InlinedScope)
return InlinedScope;
DebugLoc InlinedLoc = DebugLoc::getFromDILocation(InlinedAt);
InlinedScope = new LexicalScope(getOrCreateLexicalScope(InlinedLoc),
DIDescriptor(Scope), InlinedAt, false);
InlinedLexicalScopeMap[InlinedLoc] = InlinedScope;
LexicalScopeMap[InlinedAt] = InlinedScope;
return InlinedScope;
}
/// getOrCreateAbstractScope - Find or create an abstract lexical scope.
LexicalScope *LexicalScopes::getOrCreateAbstractScope(const MDNode *N) {
assert(N && "Invalid Scope encoding!");
LexicalScope *AScope = AbstractScopeMap.lookup(N);
if (AScope)
return AScope;
LexicalScope *Parent = NULL;
DIDescriptor Scope(N);
if (Scope.isLexicalBlock()) {
DILexicalBlock DB(N);
DIDescriptor ParentDesc = DB.getContext();
Parent = getOrCreateAbstractScope(ParentDesc);
}
AScope = new LexicalScope(Parent, DIDescriptor(N), NULL, true);
AbstractScopeMap[N] = AScope;
if (DIDescriptor(N).isSubprogram())
AbstractScopesList.push_back(AScope);
return AScope;
}
/// constructScopeNest
void LexicalScopes::constructScopeNest(LexicalScope *Scope) {
assert (Scope && "Unable to calculate scop edominance graph!");
SmallVector<LexicalScope *, 4> WorkStack;
WorkStack.push_back(Scope);
unsigned Counter = 0;
while (!WorkStack.empty()) {
LexicalScope *WS = WorkStack.back();
const SmallVector<LexicalScope *, 4> &Children = WS->getChildren();
bool visitedChildren = false;
for (SmallVector<LexicalScope *, 4>::const_iterator SI = Children.begin(),
SE = Children.end(); SI != SE; ++SI) {
LexicalScope *ChildScope = *SI;
if (!ChildScope->getDFSOut()) {
WorkStack.push_back(ChildScope);
visitedChildren = true;
ChildScope->setDFSIn(++Counter);
break;
}
}
if (!visitedChildren) {
WorkStack.pop_back();
WS->setDFSOut(++Counter);
}
}
}
/// assignInstructionRanges - Find ranges of instructions covered by each lexical
/// scope.
void LexicalScopes::
assignInstructionRanges(SmallVectorImpl<InsnRange> &MIRanges,
DenseMap<const MachineInstr *, LexicalScope *> &MI2ScopeMap) {
LexicalScope *PrevLexicalScope = NULL;
for (SmallVectorImpl<InsnRange>::const_iterator RI = MIRanges.begin(),
RE = MIRanges.end(); RI != RE; ++RI) {
const InsnRange &R = *RI;
LexicalScope *S = MI2ScopeMap.lookup(R.first);
assert (S && "Lost LexicalScope for a machine instruction!");
if (PrevLexicalScope && !PrevLexicalScope->dominates(S))
PrevLexicalScope->closeInsnRange(S);
S->openInsnRange(R.first);
S->extendInsnRange(R.second);
PrevLexicalScope = S;
}
if (PrevLexicalScope)
PrevLexicalScope->closeInsnRange();
}
/// getMachineBasicBlocks - Populate given set using machine basic blocks which
/// have machine instructions that belong to lexical scope identified by
/// DebugLoc.
void LexicalScopes::
getMachineBasicBlocks(DebugLoc DL, SmallPtrSet<const MachineBasicBlock*, 4> &MBBs) {
MBBs.clear();
LexicalScope *Scope = getOrCreateLexicalScope(DL);
if (!Scope)
return;
SmallVector<InsnRange, 4> &InsnRanges = Scope->getRanges();
for (SmallVector<InsnRange, 4>::iterator I = InsnRanges.begin(),
E = InsnRanges.end(); I != E; ++I) {
InsnRange &R = *I;
MBBs.insert(R.first->getParent());
}
}
/// dominates - Return true if DebugLoc's lexical scope dominates at least one
/// machine instruction's lexical scope in a given machine basic block.
bool LexicalScopes::dominates(DebugLoc DL, MachineBasicBlock *MBB) {
LexicalScope *Scope = getOrCreateLexicalScope(DL);
if (!Scope)
return false;
bool Result = false;
for (MachineBasicBlock::iterator I = MBB->begin(), E = MBB->end();
I != E; ++I) {
DebugLoc IDL = I->getDebugLoc();
if (IDL.isUnknown())
continue;
if (LexicalScope *IScope = getOrCreateLexicalScope(IDL))
if (Scope->dominates(IScope))
return true;
}
return Result;
}
/// dump - Print data structures.
void LexicalScope::dump() const {
#ifndef NDEBUG
raw_ostream &err = dbgs();
err.indent(IndentLevel);
err << "DFSIn: " << DFSIn << " DFSOut: " << DFSOut << "\n";
const MDNode *N = Desc;
N->dump();
if (AbstractScope)
err << "Abstract Scope\n";
IndentLevel += 2;
if (!Children.empty())
err << "Children ...\n";
for (unsigned i = 0, e = Children.size(); i != e; ++i)
if (Children[i] != this)
Children[i]->dump();
IndentLevel -= 2;
#endif
}
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